1. Field of the Invention
This invention relates to the field of testing bone qualities and more particularly to a device for supporting a limb in a fixed position for testing bone stiffness.
2. Description of the prior Art
Many efforts have been made to test bone qualities and more particularly to determine bone stiffness. These efforts culminated in U.S. Pat. No. 5,006,984 dated Apr. 9, 1991, to Steele, the entire disclosure of which is incorporated herein by reference. Steele discloses a method and apparatus for measuring physical parameters of the bone, especially the stiffness of a bone. In order for a bone to be measured in a live subject, means must be used to support the bone to be tested.
Typically, in human bone measurements are made on the ulna bone because of its proximity of the ulna bone to the skin. It is desirable to support the ulna bone as a simple beam. In the past, measurements were made by placing the wrist and elbow in "V" blocks to support the patient's limb. As so supported, testing could take place on the bone.
Several problems developed from providing such support to the patient's limb. One problem was positioning the patient's limb over the arm support. In the elbow, its difficult to provide mechanical contact to the elbow end of the ulna because of interference by the bicep muscles with the positioning of the limb. Accordingly, consistent and reproducible results were not encouraged because of variations in the support of the limb at the location of the elbow.
The previous efforts to support a limb for testing of the bone have been unable to provide the consistent and reproducible results of the present invention because of interference of the support system with the muscles or tendons of the patient.
Previous attempts in this area are as follows:
Australian Patent No. 4022-836-A (TAB A), discloses a support for an arm comprising our lower fixed rail, a hand stop and a second stop positioned against the back of the upper arm.
Domeland, U.S. Pat. No. 4,754,763, (TAB B), discloses a method of detecting bone fractures and evaluate healing the bones by applying a mechanical vibration to the bones.
Collier, U.S. Pat. No. 4,799,498, (TAB C), discloses an apparatus for detecting the resonant frequency of a bone. The testing element pierces the skin and is brought into actual contact with the bone.
U.S. Pat. No. 5,000,168, (TAB D), discloses a limb support for use by a patient for supporting a limb on a fixed surface.
Steele, U.S. Pat. No. 5,006,984, (TAB E), discloses a method and apparatus for measuring physical parameters of a bone, for example, bone density. It includes basic V blocks for catching and positioning bones and/or limbs to be tested.
Meyer, U.S. Pat. No. 5,012,820, (TAB F), discloses a device for use in measuring mechanical magnitudes during muscular contraction. The device includes a housing for holding limbs. A foot may be held in a housing having a base plate, an upper limb holder and a lower limb holder, the upper limb holder and the lower limb holder comprising straps that extend about the limb. Also included in the invention is a housing for holding a hand a thumb for examination. The thumb is supported by a U-shaped structural component.
Palfray, U.S. Pat. No. 5,065,770, (TAB G), discloses an apparatus for plotting or determining the shape or profile of a limb. The apparatus includes a plurality of splints positioned at various intervals. The splints which are deformable and can be applied tightly against a limb to match the profile thereof.
Kurth, U.S. Pat. No. 5,069,229, (TAB H), discloses an apparatus for immobilizing a knee to prevent flexing of the knee. The apparatus comprises a split, tapered, wrapping fixed around, above and below the knee.
Bond, U.S. Pat. No. 5,078,152, (TAB I), discloses a method and apparatus for diagnosis and/or treating of proprioceptor feedback capabilities in a human muscle and joint system. The apparatus includes a passive resistance system having a lever arm assembly with a patient attachment cuff mounted thereto. This assembly allows the patient to move a limb radially during an exercise motion.
Pierela-Cruz, U.S. Pat. No. 5,136,743, (TAB J), discloses a distill radioulnar joint stress platform comprising a pair of upright blocks mounted to the platform in a spaced relationship to permit a wrist to be positioned therebetween, a post on the platform near one end thereof for gripping by the subject, and a pair of stabilizing brackets adjustably mounted to each block for contacting the side of the fore arm to hold the fore arm in a preselected position for examination.
Fry-Welsh, U.S. Pat. No. 5,163,443, (TAB K), discloses a method and apparatus for measuring hand, wrist and fore arm strength. The apparatus comprises a frame supporting a harness in the center thereof by means of a plurality of coupling links. Also included is a fore arm support for the subject to rest its fore arm
Rosen et al., U.S. Pat. No. 5,231,998, (TAB L), discloses an apparatus for steadying limb motion for limiting involuntary movement of the limb. The device includes a limb coupler cuff assembly comprising a U-shaped support coupled to a limb coupler trough or cuff in which the fore arm is held.
Siegler, U.S. Pat. No. 5,228,454, (TAB M), discloses an apparatus and method for determining load-displacement and flexibility characteristics of a joint. The apparatus includes first and second frames for receiving first and second ends of a limb. A pivot assembly is provided between the first and second frames to allow the first frame to pivot with respect to the second frame. Also included are straps for securing the limb in position between the first and second frames.
Kawamura, U.S. Pat. No. 5,228,457, (TAB N), discloses a protector for a heartbeat-synchronous pulse wave detecting probe used in the limb of a patient. The protector comprises a flat portion for positioning underneath the limb and a shield portion extending from the flat portion to protect the detecting probe from contacting any medical staff.
U.S. Pat. No. 4,297,884 to Leveque et al. discloses a method and apparatus for testing the elastic characteristics of an object. The sample to be tested is held at one end between jaws and a hooking element.
"PREDICTION OF BENDING STRENGTH OF LONG BONES FOR MEASUREMENTS OF BENDING STIFFNESS AND BONE MINERAL "CONTENT" by Borders, Peterson and Orne discloses three point and four point bending testing of bones. The support system is simple.
DETERMINATION OF MECHANICAL PROPERTIES OF THE HUMAN ULNA BY MEANS OF MECHANICAL IMPEDANCE TEST: EXPERIMENTAL RESULTS AND IMPROVED MATHEMATICAL MODEL by Thompson, Orne and Young discloses an apparatus including an electromagnetic shaker and a simple two point support for the ulna. The support at the wrist includes a strap that extends over the top of the wrist. Additionally, the device could include small plaster pads caste to conform to bony prominences at both the wrist and the elbow.
IN VIVO DETERMINATION OF THE MECHANICAL PROPERTIES OF BONE by Peterson discloses in vivo tests on a monkey wherein the fore arm rests on two supports in a manner such that the ulna can be modeled as a simply supported beam. Additional experiments were conducted on a foam foundation in a manner so that the ulna can be modeled as a beam on an elastic foundation. The subject was pushed down gently through the humerus to constrain the olecranon end of the ulna for moving. A small plastic pad made to fit the contour of the bone at both the elbow and the wrist were placed on top of each support.
NONINVASIVE DETERMINATION OF ULNA STIFFNESS FROM MECHANICAL RESPONSE-IN VIVO COMPARISON OF STIFFNESS AND BONE MINERAL by Steele, Zhou, Guido, Marcus, Heinrichs and Cheema discloses a test configuration wherein the ulna is simply supported at the wrist and elbow.
INSTRUMENT FOR ASSESSMENT OF BONE PROPERTIES by Steele discloses a test where the ulna is simply supported at the elbow and wrist. Additionally, a system showing utilizing vertical positioning of the bone under tests is disclosed.
NONINVASIVE DETERMINATION OF BONE STIFFNESS by Peterson discloses simply supporting the ulna at the elbow and the wrist. The support for the elbow was placed directly under the greater sigmoid cavity. Plaster was molded under the elbow and at the wrist so that the ulna was restrained against even small lateral motion at the supports. And further, with respect to testing a monkey arm, a two kilogram weight was placed on top of the humerus to constrain the ulna. The experiment was repeated with duct seal substituted for the plaster pads which held the ulna in position at each end. The duct seal was not only more comfortable than the plaster pads but it saved time in setting up the experiment.
Steele, U.S. Pat. No. 4,646,754, discloses a method and apparatus for inducing vibrations to elements of the human body and detecting the responses for determining mechanical characteristics of the elements. The apparatus includes a vibrator plate configured to contact the skin surface.
None of these previous attempts, taken either alone or in combination, teach or suggest the structure and the advantages and benefits of Applicant's present invention.
OBJECTS AND SUMMARY OF THE INVENTION
The apparatus of the present invention overcomes the deficiencies associated with supporting a limb with "V" blocks. The apparatus of the present invention supports the patient's elbow on support pegs that extend under the condyles of the humerus bone. The support pegs extend from behind the patient's elbow. This allows for good mechanical support of the ulna bone which is interconnected with the humerus bone at the elbow and extends over the humerus bone. When a patient's arm is positioned in the apparatus of the present invention, the ulna extends over the humerus and is positioned close to the skin in a position desirable for testing. The wrist is supported in the apparatus of the present invention between two vertical support pegs to secure the wrist in a vertical position and to prevent radial movement of the wrist. Again, this works to properly position the ulna above the humerus and allows for consistent, reproducible results during testing performed on a bone.
Accordingly, it is an object of the limb supporter apparatus of the present invention to provide an apparatus for supporting a limb for testing a bone.
It is a further object of the limb supporter apparatus of the present invention to support the ulna bone for testing.
It is a still further object of the limb supporter apparatus of the present invention to provide mechanical support of a limb at the ends of the limb.
It is another object of the limb supporter apparatus of the present invention to support an arm with support pegs positioned below the condyles of the humerus.
It is yet another object of the limb supporter apparatus of the present invention to support a arm with vertical support pegs positioned along the wrist.
It is still a further object of the limb supporter apparatus of the present invention to provide results that can be reproduced.
It is even another object of the limb supporter apparatus of the present invention which will position a patient's arm consistently in the same position.
It is an additional object of the limb supporter apparatus of the present invention to position both the right and left arms of a patient for testing.
It is yet an additional object of the limb supporter apparatus of the present invention to be easily adjusted to the patient's size.
It is still an additional object of the limb supporter apparatus of the present invention to stabilize a limb for other applications such as performing tests on a bone that is covered by a cast.
It is a further object of the limb supporter apparatus of the present invention to have other applications such as stabilizing a limb for CT or MRI testing.
It is even a further object of the limb supporter apparatus of the present invention to stabilize a limb for surgical procedures.
These as well as further objects and advantages of this invention will become apparent to those skilled in the art from a review of the accompanying detailed description of the preferred embodiment, reference being made to the accompanying drawings.